Enameled metallic vessel.



W. A. DUNLAP. ENAMELED METALLIC VESSEL.

APPLICATION FILED AUG.26 1914.

Patented Dec. 28, 191.5.

mam

R O T N E V N WILLIAM A. DUNLAP, OF PITTSBURGH, PENNSYLVANIA.

ENAMELED METALLIC VESSEL.

Specification of Letters Patent.

Patented Dec. 28, 11915.

Application filed August 26, 1914. Serial No. 858,707.

To all whom it mayconcerni ments in Enameled Metallic Be it known that I, WILLIAM A. DUNLAP, residing at Pittsburgh, in the county of Allegheny and State of Pennsylvania, a citizen of the United States, have invented or discovered certain new and useful Improve- Vessels, of which improvements the following is a specification.

The invention described herein relates to metallic vessels, such, for example, as liquid or gas containers, vacuum insulated metal refrigerators, metal thermos bottles, etc., the metal walls of which are all or in part provided with a coating of vitreous enamel. In vessels of this character, and particularly Vessels adapted to contain fluid under pressure or to inclose a rarefaction space, it is frequently desirable or necessary to provide a passageway through an orifice in the enameled wall, such passageway being for the purpose of filling or dischargin the vessel, or, in the case of vacuum insu ated vessels, for exhausting the rarefaction space. Considerable difliculty has been experienced in efi'ecti'ng a durable fluid-tight connection of such passageway to the enameled wall. For example, it will be understood that, in attaching a passageway to such articles, localized pressure may not be applied to surfaces coated with vitreous enamel withoutliability of breaking or otherwise injuring the enamel, and, when cements are employed to seal the connection of a tube or passage way to the wall, they eventually disintegrate sufficiently to cause greater or less leakage. It is toward this particular feature of the construction of enameled articles that my invention is primarily directed, and the ob ject thereof is to provide a passageway leading from an orifice in an enameled metal ves-- sel, the attachment of such passageway to the wall surrounding the orifice being fluidtight, durable and practical.

While my invention may be used in vessels adapted to be emplo ed for different specific purposes, as already indicated, it is particularly applicable to vacuum insulated vessels, and is shown herein in its adaptability to a metal walled thermos bottle.

In the accompanying sheet of drawing, which forms part of my specification, Figure 1 is a central longitudinalsection View of a thermos bottle embodying my invention, and Fig. 2 is an enlarged view ofthe passageway through the outer wall of the bottle.

-wall 5 and the outer wall In the practice of my invention I provide the enameled metal wall of a vessel with an orlfice, and, extending from such orifice, I provide a vitreous tube which is fused to the vitreous enamel coating adjacent to the orifice, thereby affording a hermetically sealed connectlon between the tube or passageway and the enameled metal wall. The manner in which the vitreous tube may be thus attached 1S fully explained in my copending application, Serial No. 858,706. Briefly stated, the tube may be inserted in the orifice before the enameling process, and being su tably supported therein, its outer wall Wlll become fused to the enamel coating as such coating is applied; or the article may be enameled before inserting the tube, in which event the enamel is heated afterinserting the tube and caused to fuse with its outer wall. I

In the illustrative embodiment of my invention, the vitreous-tube 1, which may be of clear glass, projects through an orifice 2 in the bottom portion of the outer wall 3 of a two-wall thermos bottle, made preferably of sheet metal. The exterior surface of the wall 3 is provided with a coating of vitreous enamel 4.- which is fused with the outer wall of the tube. As originally in? serted, the tube is of course open at both ends. After the space between the inner 3 has been rarefied, .the outer end of the tube may be heated and sealed by means of its plastic body. However, various other expedients may, in the practice of my invention, be employed for permanently closing the tube, or for controlling fiow therethrough.

Preferably the bottom portion of the wall 3 is concave, as shown, and is formed into a ring 6 adapted to receive a cap 7, there bemg a suitable protecting packing 8 between v the cap and the wall '3 and tube 1. The inner and outer walls 5 and 3, respectively, are each preferably formed of a single integral blank of sheet metal, and are joined together at the top by a roll seam sealed by the vitreous enamel coatings. I In manufacturing the bottle, the two walls, in substantially cylindrical forms, are placed one within the other, and, by suitable metal-spinning apparatus, brought to the forms indicated in the drawing. By thus providing an adequiate passageway for exhausting the rarefaction space of a vacuum insulated metallic vessel having a coating of vitreous enamel,

I gain further advantages in the construction of such vessels. It is well known that some metals (and this is true of sheet steel) are slightly pervious to gases, particularly after such metals have been subjected to mechanical strain beyond their elastic limit. In forming vessels such as shown herein it is of course necessary to thus strain the metal. However, since by the practiceof my invention enameling of such vessels is rendered feasible and practical, the strains are removed by the necessary heating and gradual cooling of the coated walls, and the vitreous layer renders the entire metal surface, whether previously strained 0r not,- impervious to gas. It is furthermore characteristic of enameled metal vacuum-insulated vessels that they may be readily cleansed by hot water without liability of breaking them, and they will stand much rougher usage than glass-walled vessels of the same gen-- eral character.

I claim as my invention:

1. A vessel having a metal wall provided with an adherent coating of vitreous enamel; an orifice through'such wall; and a vitreous tube leading-from, and fused to the vitreous enamel coating adjacentto, such orifice.

2. A vacuum insulated vessel comprising inner and outer metallic walls affording a rarefaction space between them, one wall being provided with an adherent coating of vitreous enamel and further provided with an orifice having a vitreous tube extending from it, the tube being fused to the enamel coating adjacent to the orifice.

3. A vacuum insulated vessel comprising inner and outer metallic walls affording a rarefaction space between them, the interior of the inner Wall and the exterior of the outer wall being provided with adherent coatings Copies of this of vitreous enamel, an orifice through the outer wall, and a glass tube extending from such orifice, the outer surface of such tube being fused to the enamel coating adjacent to said orifice, and the outer end of the tube being closed by glass integral with the tube body. 1

4. A vacuum insulated ,vessel comprising inner and outer metallic walls affording a rarefactionspace between them and each provided with an adherent coating of vitreous enamel, the bottom portion of the outer wall being concave and provided with an orifice, a closed vitreous tube extending from such orifice and fused to theenam'el adjacent to the orifice, and means forprotecting the outer end of said tube.

5. A vacuum insulated vessel comprising inner and outer metallic walls affording a ,rarefaction space between them, each wall besuch fusion of the tube to the enamel afford ing the sole means of connecting the tube to the .vessel.

In testimony whereof I have hereunto set my hand. Y

WILLIAM A. DUNLAP. Witnesses:

PAUL N. CRrroHLow, FRANCIS J. TOMASSQN.-

patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

